Alex Iwobi will be fined by Arsenal if he is found to have partied until the early hours of Saturday morning ahead of Sunday's FA Cup defeat to Nottingham Forest.

The 21-year-old forward was filmed dancing in central London at 2.37am on Saturday in a video uploaded to Snapchat, according to The Sun.

He then played 90 minutes at the City Ground as the holders crashed out, going down 4-2 to Sky Bet Championship side Forest.

Arsenal manager Arsene Wenger said: "Yes, if that is true he will be fined. It is impossible to go out 48 hours before a game. It is unacceptable."

Iwobi was reported to have attended a party that included people smoking cannabis and inhaling laughing gas.

But Wenger said his player was not involved in either taking drugs or drinking alcohol.

"First of all we have to be cautious with everything that is coming out," Wenger said.

"When you read what is reported it is like he has taken drugs. He was not involved in that at all.

"He has been out at a birthday party and how long he has stayed? That is important. After, I will decide what happens.

"Did he do drugs or alcohol? Not at all. If your neighbour takes drugs, what can you do? You are responsible for your own behaviour, not the behaviour of your neighbour."

Wenger admitted Iwobi's performance against Forest may have been affected.

"Who knows that?" Wenger said. "You know that sometimes you want to prepare 100 per cent but it is not always a guarantee you will be at your best.

"But that is what is requested from a top-level professional."

Wenger is yet to decide whether Alexis Sanchez will face Chelsea in Wednesday's Carabao Cup semi-final, amid speculation the forward could join Manchester City this month.

The Arsenal manager insisted no club has yet made contact over Sanchez but, asked if he expects the Chilean to stay, Wenger said: "I expect nothing."

Another player who could leave is Francis Coquelin. Wenger admitted "it is a possibility" the midfielder could be let go but said reports suggesting a deal is agreed with West Ham are wide of the mark.

Wenger also remained tight-lipped on rumoured interest in Jonny Evans but conceded, if it came down to it, Arsenal would lose a financial fight with Manchester City over the West Brom defender.

Arsenal will be looking to bounce back from the Forest defeat at Stamford Bridge but they are not expecting any injured players back for the first leg.

Granit Xhaka and Shkodran Mustafi will both undergo late fitness tests, while Wenger will serve the second of a three-game touchline ban.

"We take the criticism on board and respond to it in a positive way - that's all you can do," Wenger said.

"We're in the semi-final of the League Cup and we have an opportunity to go through."